Surface-based assays for the detection of oligonucleotides have previously been described. While these assays often include additional steps such as the inclusion of “capture” sequences pre-bound to the surface of the material, or post-assay testing procedures that are effectively visual aids that render a “black box” technology more palatable for market use, the primary issue with the vast majority of systems currently offered is the dependence on the polymerase chain reaction (PCR) to give suitable amplification of the target strand.
Advances in the PCR system since its first inception have reduced the amount of time required to satisfactorily amplify a target oligonucleotide up to detectable levels. However, even real-time PCR systems can take upwards of several hours to produce a definitive positive or negative response, the reaction is sensitive to the presence of contaminants, and repeated cycles of heating and cooling at specific temperature plateaus means that the PCR device is expensive and, with constant use, energy intensive.
The need for a rapid, reliable and economical oligonucleotide testing procedure is steadily growing throughout the world's health services. Although several technologies have seen development in recent years, the primary testing method for infectious agents such as Multi or Methicillin Resistant Staphylococcus aureus (MRSA) and strains of Clostridium difficile remains the growth of cultures on selective media. For viruses, viral load is determined by methods including PCR, branched DNA (bDNA), and NucliSENS extraction—the latter two examples being more suited to the extraction and quantification of larger viral loads. The necessity of testing for the presence of microorganisms that endanger immuno-compromised individuals (particularly in hospitals) such as MRSA has been recognised in proposed legislation from the UK and USA governments. Current testing methods are slow or require specialist technical skill with complicated laboratory facilities which are unsuitable for some hospital situations.
Aside from medical use, the testing method could be readily used to identify the presence of micro-organisms in the environment, such as in soil and water for agricultural and hygiene testing, and in forensic applications for the transfer of biologically-derived materials.